Draw roll and temperature gauge for draw-twisting, draw-winding and spin-draw-winding machines

ABSTRACT

The draw roll is provided with a stationary temperature gauge positioned in slightly spaced relation to the inside surface of the draw roll. The temperature gauge is elongated along the middle region of the draw roll while the gap between the gauge and draw roll corresponds to the thickness of the air boundary layer which permits the most direct heat transfer. The gauge thus has a short response timelag.

United States Patent Inventors Felix Graf Wiuterthur; Armin Wirz, Dietlikon, both of Switzerland Appl. No. 874,544 Filed Nov. 6, 1969 Patented Jan. 4, 1972 Assignee Rieter Machine Works, Ltd. Priority Nov. 6, 1968 Switzerland 16658/68 DRAW ROLL AND TEMPERATURE GAUGE FOR DRAW-TWISTING, DRAW-WINDING AND SPIN- DRAW-WINDING MACHINES 13 Claims, 4 Drawing Figs.

US. Cl 219/10.6l, 219/469 Int. Cl 1105!) 5/00, 1105b 9/06 Field of Search 73/351' [56] References Cited UNITED STATES PATENTS 3,211,893 10/1965 Barlow et a1 219/494 X 3,412,229 11/1968 Seagrave 219/471 X 3,414,711 12/1968 Guyet et al. 165/89 X 3,435,171 3/1969 Lohest 219/471 X 3,500,019 3/1970 Childress.... 219/471 X Primary Examiner-J. V. Truhe Assistant Examiner-Hugh D. Jaeger Attorney-Kenyon & Kenyon Reilly Carr & Chapin ABSTRACT: The draw roll is provided with a stationary temperature gauge positioned in slightly spaced relation to the inside surface of the draw roll. The temperature gauge is elongated along the middle region of the draw roll while the gap between the gauge and draw roll corresponds to the thickness of the air boundary layer which permits the most direct heat transfer. The gauge thus has a short response timelag.

DRAW ROLL AND TEMPERATURE GAUGE FOR DRAW- TWISTING, DRAW-WINDING AND SPIN-DRAW- WINDING MACHINES This invention relates to a draw roll and temperature gauge for draw-twisting, draw-winding and spin-draw-winding machines.

It has been known that the drawing arrangements for endless filaments on machines such as draw twisters, draw winders and spin-draw-winders contain a large number of draw rolls, which must be heated in order to transfer heat to the filaments placed onto the rolls. Initially, heating of the draw rolls was effected by a simple control of all the rolls for constant power. As the temperature in such an arrangement was maintained within admissible limits on some of the draw rolls but exceeded on others. the installation of a temperature gauge at each draw roll became mandatory. Such temperature gauges were then used via an individual control device, to influence the heating and thus the temperature of each draw roll.

For example, in heating by means of a stationary resistance heating device arranged inside the draw roll, the temperature gauge has frequently been mounted in the heating device inside the roll in order to control the temperature of the heating device. However, the temperature of the heating device has been considerably higher than the actual roll temperature due to reasons of the heat transfer across the airgap necessarily present between the heating device and the rotating draw roll. In addition, it is noted that a resistance heating device has a very inert reaction and that the drop in temperature between the draw roll circumferential periphery and the heater depends substantially on the load.

As an alternative, the temperature gauge has also been arranged in the rotating draw roll wall. This arrangement has been possible if induction or resistance heating have been used. However, while the temperature gauge has thus been capable of being arranged at the most suitable location so that the true roll temperature can be measured there correctly, it has been a disadvantage of this arrangement that the measured temperature must be transmitted, as by a signal, from the rotating roll to a stationary control device. This has required that such transmitting devices as collector brushes, mercury, inductive noncontacting, etc. devices be used for this purpose. In order to avoid the difliculties involved in the transmission of signals, the heater and the control device also can be accommodated in the rotating system. In this arrangement, however, adjustments of the control device as well as transfer of the heating energy can only be effected satisfactorily under difficulties. Consequently, all solutions of this type have necessitated expensive arrangements, have been susceptible to disturbances and furthermore have yielded unreliable measuring results.

It has also been known to provide a stationary temperature gauge which protrudes into a narrow angular groove at the back of a draw roll concentric with the rotational axis so that the gauge takes the temperature of the air heated by the roll rotating in the groove. In this solution, however, the room inside the draw roll cannot be fully utilized, but can only be partially utilized as the draw roll wall thickness must be chosen such that the annular groove can be accommodated. A further considerable disadvantage of this arrangement is that for mounting reasons, the temperature gauge must be arranged in close vicinity of the back end of the draw roll.

As is well known, the temperature profile of an operating draw roll varies in the axial direction, the maximum usually being found approximately near the middle of the draw roll. It is thus possible to influence the distribution of the heating in an axial direction within certain limits by design measures in order to achieve a somewhat flatter temperature distribution. This influence, however, at best can ensure a certain temperature distribution only for a certain operating condition determined by rotational speed and the heat transfer to the material processed. Under changed load conditions, but otherwise correct control, the temperature profile curve along the draw roll thus will pivot around the location of the temperature gauge,

Le. the temperature will be maintained at the measuring point but not at adjacent places. An array of different temperature profile curves results, intersecting at the measuring point. In particular, the latter solution mentioned above implies that at the point where the cold thread is placed upon the roll in the vicinity of the back roll end, should the temperature tend to drop at that point, additional heat energy would be applied in order to maintain the temperature. The temperature would then increase at the middle zone and at the front end of the draw roll as the thread arriving there is already heated. The temperature thus increases just at the very place where it should be kept constant, namely near the point where the thread is transferred into the drawing zone. In short draw rolls, such as used on draw twisting machines, this disadvantage is of less consequence as in the very long draw rolls used on spindraw-winding machines since in order to achieve longer contacting times of the thread on the roll, longer draw rolls are needed due to the usually high processing speeds used on such machines.

Accordingly, it is an object of the invention to measure the temperature on a draw roll at the very place where the most reliable measuring results are achieved. It is another object of the invention to measure the temperature of a draw roll in a manner to compensate for the curved temperature profile of the draw roll.

It is another object of the invention to keep the deviation of the measured temperature from the temperature at the draw roll circumference as small as possible.

It is another object of the invention to avoid temperature variances between the different individual draw rolls.

Briefly, the invention provides a draw roll of a draw-twisting, draw-winding or spin-draw-winding machine with a temperature gauge which is stationarily mounted with respect to the draw roll and which measures the temperature of the heated roll without contact. For example, where the draw roll has a cylindrical wall onto which a filament or thread is placed and an induction-heating device disposed inside the draw roll in a stationary manner with respect to the frame of the machine, the gauge is disposed to face the inside cylindrical wall surface of the draw roll and is fixedly mounted to leave a small airgap between the wall surface and the gauge. The gauge is of flat shape and is disposed in the middle region of the draw roll. In addition, the gauge is isolated against heat transmission from the induction-heating device.

In one embodiment, the gauge can be foil shaped and mounted in an insulated manner on the induction-heating device while in another embodiment the gauge can be mounted on a holder and disposed in spaced relation to the induction-heating device as well as the draw roll. In this latter embodiment, the holder can be fixed into the heating device to facilitate mounting of the temperature gauge.

In still another embodiment the temperature gauge can be shaped as a narrow rodlike strip while extending axially of the draw roll.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a longitudinal cross-sectional view of a draw roll utilizing a temperature gauge according to the invention;

FIG. 2 illustrates a longitudinal cross-sectional view of a modification according to the invention;

FIG. 3 graphically illustrates a series of temperature profile curves along a draw roll; and

FIG. 4 illustrates a fragmentary view of a further modification according to the invention.

Referring to FIG. 1, a draw roll 1 is threaded to a drive shaft 3 which is supported in gear housing 2. In addition, a heating device 4 is supported, or carried, on a holder 5 and is rigidly connected with the gear housing 2 in a stationary manner. The heating device 4 consists of a magnetic conductive cylindrical core 6 having lateral flanges 7, 8 protruding radially outwardly into close vicinity to the cylindrical inside surface 9 of the draw roll wall 10. In addition, an induction spool 11 surrounds the core 6 as is known.

in order to measure the temperature of the draw roll 1, a flat very thin temperature gauge 12 in the shape of an area thermometer is placed onto the spool 11 approximately at the middle of the draw roll wall 10 facing the inside surface 9. The clearance between the temperature gauge 12 and the inside draw roll wall surface 9 is of 0.3 to 1 mm., compared to a draw roll diameter of at least 75 mm., the temperature gauge 12 also being of substantial axial length. The airgap of 0.3 to 1 mm. advantageously corresponds about to the thickness of the air boundary layer which permits the most direct heat transfer at the nominal speed of the draw roll 1. The gauge 12 is further spaced from the induction spool 11 by a foil 13 which insulates electrically as well as against heat transfer. This foil 13 should be heat resistant and saturated with insulating lacquers and should be mechanically sufficiently resistant for protecting of the outermost wraps of the spool 11. Materials meeting these requirements are films of Papton-polymide or Nomex papers can also be considered, both registered trademarks of the DuPont Company. The relatively long axial dimension and the extreme flatness of the gauge 12 is apt to ensure fast heat transfer from the inside surface 9 of the draw roll wall 10 to the gauge 12 which permits short response timelag. The gauge may also, if wanted, be of considerable width along the cylindrical inside surface 9.

The temperature gauge 12 is further connected, as is known, for example, electronically, to a suitable control unit R which can be used to emit a control signal in response to the measured temperature for control of the heating device 4. Since such is well known further description is not deemed to be necessary.

Referring to FlG. 2, the temperature gauge 14 can also be mounted onto a gauge holder 14' of annular U-shaped section or profile. In such a case, one leg of the U-shaped holder 14' is fastened by means of the exterior wraps 16 of the induction spool 17 to the spool while the other leg mounts the temperature gauge 14. The temperature gauge 14' is thus mounted with a minimum clearance towards the draw roll inside surface as above as well as with a considerably larger airgap between the temperature gauge 14' and the spool 17. This latter airgap serves to provide heat insulation between the gauge 14' and spool 17 and must be chosen sufficiently large so that the temperature gauge 14' is influenced only by the draw roll wall.

Referring to FIG. 3, a temperature profile is plotted as it results under different operating conditions if a thin draw roll wall is used as desirable for low inertia, the temperature gauge being arranged in the middle region, i.e., arranged as indicated in FIGS. 1 and 2. Curve a (solid line) indicates the roll surface temperature profile of the roll at standstill and without a filament or thread thereon. As no heat is drained off unevenly by ventilation or otherwise to the surrounding room, the profile curve is substantially horizontal. Curve 1; (dashed line) shows the temperature profile of the rotating roll without heat transfer to a filament or thread not yet placed onto the roll. The heat drain from the roll ends to the surrounding air is clearly demonstrated by the drop in temperature at the front and back end of the roll surface. The temperature drops most at the point A where the cold filament contacts the roll (dashdotted line, curve however, this does not cause unfavorable influences as the incoming filament is considerably colder than the draw roll wall surface. On the other hand, the unchanged temperature profile over the second half of the contacting time of the filament on the roll proves favorable as the filament temperature at the point B where the filament leaves the roll, i.e., upon entering the drawing zone, is maintained constant, which is decisive for correct drawing operation. Furthermore, in setting filaments on the draw roll, it proves advantageous to maintain the temperature constant during the contacting time of the filament on the draw roll once the filament has reached the setting temperature (zone C-B).

It thus is evident, that the temperature gauge arrangement according to the invention is much more advantageous than, e.g., measuring of the temperature at the points where the filament or thread meets or leaves the draw roll, i.e., at the back or front ends respectively, as in the prior art.

it is noted that other temperature gauges can be used in the invention. For example, area thermometers such as resistance thermometers made e.g., from metal or platinum which are designed induction free can be used or foil thermometers of a type known as such can be used.

Referring to FIG. 4, the temperature gauge 18 can also be shaped as a narrow rodlike strip extending in axial direction and can be placed onto a holder 20 which again is tied in by wraps 19 to an induction spool. Here also, the clearance towards the draw roll inside wall surface is very small and the clearance towards the wraps 19 located below is considerable as described above with respect to FIG. 2.

What is claimed is:

1. In combination with a rotatable draw roll having a cylindrical wall for receiving a filament, and an induction-heating device disposed inside said draw roll in stationary relation thereto for heating said draw roll; a temperature gauge disposed inside said draw roll in spaced facing relation to said cylindrical wall for measuring the temperature of said heated draw roll without contacting said draw roll, said gauge being in stationary relation to said draw roll and being spaced from said draw roll wall by an airgap in the range of approximately 1/250 to l/75 of the diameter of said draw roll.

2. The combination as set forth in claim 1 wherein said gauge has a relatively long axial dimension and is of considerable width along said draw roll cylindrical wall.

3. The combination as set forth in claim 1 wherein said gauge is of an elongated flat thin shape.

4. The combination as set forth in claim 1 wherein said gauge is disposed axially of a middle region of said draw roll wall.

5. The combination as set forth in claim 1 wherein said heating device includes a plurality of windings and which further comprises a holder having one leg secured in said windings and another leg supporting said gauge thereon.

6. In combination with a rotatable draw roll having a cylindrical wall for receiving a filament, an induction-heating device disposed inside said draw roll in stationary relation thereto for heating said draw roll, said heating device being spaced from said draw roll wall to define an annular airgap therebetween; a temperature gauge disposed inside said draw roll within saidannular airgap in spaced facing relation to said cylindrical wall for measuring the temperature of said heated draw roll without contacting said draw roll, said gauge being in stationary relation to said draw roll and being located wholly within the middle region of said draw roll wall; and means mounting said temperature gauge in said airgap.

7. The combination as set forth in claim 6 wherein said gauge is isolated against heat transmission from said induction heating device.

8. The combination as set forth in claim 1 wherein said gauge is spaced from said heating device by an airgap of a thickness greater than the spacing of said gauge from said draw roll wall.

9. The combination as set forth in claim 1 which means further comprises a U-shaped holder having one leg fastened to said heating device and another leg supporting said gauge thereon.

10. The combination as set forth in claim 1 wherein said gauge is a narrow rodlike strip extending axially of said raw roll.

11. The combination as set forth in claim 1 wherein said gauge is of flat shape.

12. The combination as set forth in claim 6 which further comprises heat transfer insulation between said gauge and said heating device.

13. The combination as set forth in claim 12 wherein said insulation is a tin heat and electrical insulating foil.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent; No, 3,632,947 D t d January 4, 1972 Inventor(s) 3 iX Graf et a1 It is certified that error'appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet, the figure shown at the bottom of the Abstract should appear as shown below:

Signed and sealed this 4th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents RM (10-69) USCOMM-DC scan-ps9 U.$ GOVERNMENT PRINTING OFFICE: [9'9 -365-334,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pa 3,632,947 Dated January 4, 1972 Inventor(s) Felix Graf et 1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet, the figure shown at the bottom of the Abstract should appear as shown below:

Signed and sealed this 4th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents "ORM PO-1050 (IO-69) USCOMM-DC 60376-P69 v u.s. GOVERNMENT PRINTING OFFICE: I969 o-ass-sam UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent; No. 3,632,947 Dated January 4, 1972 Inventor(s) 3 iX Graf et a1 It is certified that error'appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet, the figure shown at the bottom of the Abstract should appear as shown below:

Signed and sealed this 4th day of July 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PC4050 (w'sg) uscoMM-Dc 60376-P69 v.5. GQVERNMENT PRINTING OFFICE: '99 036533T 

1. In combination with a rotatable draw roll having a cylindrical wall for receiving a filament, and an inductionheating device disposed inside said draw roll in stationary relation thereto for heating said draw roll; a temperature gauge disposed inside said draw roll in spaced facing relation to said cylindrical wall for measuring the temperature of said heated draw roll without contacting said draw roll, said gauge being in stationary relation to said draw roll and being spaced from said draw roll wall by an airgap in the range of approximately 1/250 to 1/75 of the diameter of said draw roll.
 2. The combination as set forth in claim 1 wherein said gauge has a relatively long axial dimension and is of considerable width along said draw roll cylindrical wall.
 3. The combination as set forth in claim 1 wherein said gauge is of an elongated flat thin shape.
 4. The combination as set forth in claim 1 wherein said gauge is disposed axially of a middle region of said draw roll wall.
 5. The combination as set forth in claim 1 wherein said heating device includes a plurality of windings and which further comprises a holder having one leg secured in said windings and another leg supporting said gauge thereon.
 6. In combination with a rotatable draw roll having a cylindrical wall for receiving a filament, an induction-heating device disposed inside said draw roll in stationary relation thereto for heating said draw roll, said heating device being spaced from said draw roll wall to define an annular airgap therebetween; a temperature gauge disposed inside said draw roll within said annular airgap in spaced facing relation to said cylindrical wall for measuring the temperature of said heated draw roll without contacting said draw roll, said gauge being in stationary relation to said draw roll and being located wholly within the middle region of said draw roll wall; and means mounting said temperature gauge in said airgap.
 7. The combination as set forth in claim 6 wherein said gauge is isolated against heat transmission from said induction heating device.
 8. The combination as set forth in claim 1 wherein said gauge is spaced from said heating device by an airgap of a thickness greater than the spacing of said gauge from said draw roll wall.
 9. The combination as set forth in claim 1 which means further comprises a U-shaped holder having one leg fastened to said heating device and another leg supporting said gauge thereon.
 10. The combination as set forth in claim 1 wherein said gauge is a narrow rodlike strip extending axially of said draw roll.
 11. The combination as set forth in claim 1 wherein said gauge is of flat shape.
 12. The combination as set forth in claim 6 which further comprises heat transfer insulation between said gauge and said heating device.
 13. The combination as set forth in claim 12 wherein said insulation is a thin heat and electrical insulating foil. 